Re: ATM Revolutionary Optical Test

[astillma@nit.AirTouch.COM (Anthony Stillman)]

All and Bill too,

I've gotten enough interest in a full discussion of the Hartman test that I've 
already agreed to write up somthing with a few fewer asides and some additional
detail.  I'll work on it tonight, but please, as if I have to ask, don't let 
that stop the old hands from having a full out discussion now.

A few comments to start.  First, diffraction effects do have to be considered.
This is what limits the size of the holes and hence the regions under test.  
Second, a CCD can be used, but CCD's are small and the Hartman relies on the 
large extent of the film to increase the accuracy of the derived slopes. 
Lastly, again with the small CCD's, its hard to identify which hole goes with
which spot close to the radius of curvature.  

You can see an example of a hartman mask on the group 70 web page.
http://www.hpl.hp.com/astro/group70/
Yes, I made it out of foam core. Surplus, reused, cost nothing.


Anthony
PS By limits hole size, I mean how small you can make them.